Track forum general chit chat.

[chocstraw]

Originally Posted by omgzirra_exe

i remember watching a video of a guy selling off his GT3 to buy a Schirmer V8 GT spec E92 M3... and it was the best decision he ever made lol. running cost was cheaper, and the car was just as fast if not faster.

I convinced him to buy it in early March 2020 with the promise that "if you don't like it, I promise you won't lose money on it". Best possible time before the supercar explosion with the financial wackiness of Covid. Now it's worth like 30k more (Loaded, PTS).

and it took a ton of work to get him off the desire for a high HP turbo. Unless you do tons of custom work, turbos ain't like they used to be. Lag used to be kinda desirable. Turbos aren't even available with manuals unless you get that ridiculous 300k Sport Classic with the 7 speed.

I guess what I'm saying is, it's great. It's not $230k great. But yeah, the speed district GT3 guys generally rule, super fast, and I get their desire for them. The GT cars just work and don't quit.

Originally Posted by spooni

Getting some OEM Goodyear SC3 to replace the all seasons that the original owner put on.

SC3Rs are such good tires.

They are like ice unless driven hard though. Needs heavy braking for ~5 mins

[TheMechanic]

I don't know what you guys are talking about... I track my cars and my M3 is much slower than my GT3.. Wait. I don't have a GT3, I only dream of one.

Nevermind.

[M1500Z]

I wish the track forums were merged into one group. I'll now be posting across E9X, F8X, and F87 😅, but this area has probably got the most in-depth discussion around tires. I'd like to get some experienced input to offset my inexperience as I try to understand why I was slower and why my tire wear is worse on a supposedly fast tire.

Background
I recently tried out a set of Goodyear SC3 R for a weekend and was a bit surprised by the tire. Surprised in that I was a hair slower than my PB on worn RE-71RS of the same 275/35-18 size with the exact same setup. The Goodyears were more consistent but never felt quite as grippy, especially at the front end. Looking at the wear, the outside shoulder looks a bit knackered. Even though I was about .5s slower, I spent most of my time about 1-1.5s off that PB.

For comparisons sake
Hot pressures: SC3 R at ~36psi / RE-71RS at ~35psi
Ambient temps: 58º / 64ºF.
COTA lap times: 2:29.8 / 2:29.3

Car setup
F87 M2 comp
14k fr 12k rr spring (true coilover)
CS Racing bars set to soft
-3.2º fr / -2.3º rr camber
0mm fr / .15mm rr toe
7º fr caster
Smidge of rake, corner balanced, and no aero

Pics of the SC3 R after 1 weekend (don't have pics of the RE-71RS but they wore pretty well)

Front left (front right is basically a mirror)







Rears (left on left, right on right)



So why was I slower and what's with that front wear?

• Is this a tire pressure issue? Feel like I'm in the ballpark given pyro readings
• Is this an alignment issue? That outside shoulder wear is not great and I did not hammer these tires cold
• Is it a setup issue—with a stickier tire, shouldn't it still be faster even if the car isn't in the "ideal" setup?
• Is this from over driving the car?
• Is the RE-71RS just that damn good? They were not as inspiring at full tread depth and they don't handle heat as well, but they are certainly quick when worn.

I've got your basic Aim Solo2 DL/Smarty cam setup so can likely answer data questions if asked. I appreciate any thoughts or input! 👏🏻 🙇🏻*♂️

[omgzirra_exe]

Originally Posted by M1500Z

I appreciate any thoughts or input! ���� ����*♂️

do you have a pic of the sidewall marker?

my one time experience with S3 at 36F and 34PSI hot temp on a full weight E92 M3, on a technical track like BW in SoCal,

i think for COTA you might want to start at a higher cold temp... with a slightly higher hot temp due to more extended high speeds?

although im barely a sub 2 guy at BW so my experience isn't much...

[spxxx]

Originally Posted by M1500Z

I wish the track forums were merged into one group. I'll now be posting across E9X, F8X, and F87 😅, but this area has probably got the most in-depth discussion around tires. I'd like to get some experienced input to offset my inexperience as I try to understand why I was slower and why my tire wear is worse on a supposedly fast tire.

Background
I recently tried out a set of Goodyear SC3 R for a weekend and was a bit surprised by the tire. Surprised in that I was a hair slower than my PB on worn RE-71RS of the same 275/35-18 size with the exact same setup. The Goodyears were more consistent but never felt quite as grippy, especially at the front end. Looking at the wear, the outside shoulder looks a bit knackered. Even though I was about .5s slower, I spent most of my time about 1-1.5s off that PB.

For comparisons sake
Hot pressures: SC3 R at ~36psi / RE-71RS at ~35psi
Ambient temps: 58º / 64ºF.
COTA lap times: 2:29.8 / 2:29.3

Car setup
F87 M2 comp
14k fr 12k rr spring (true coilover)
CS Racing bars set to soft
-3.2º fr / -2.3º rr camber
0mm fr / .15mm rr toe
7º fr caster
Smidge of rake, corner balanced, and no aero

Pics of the SC3 R after 1 weekend (don't have pics of the RE-71RS but they wore pretty well)

Front left (front right is basically a [...]

I don't have SC3R experience but the RE71RS tires are magic. The SC3R is fast but you're right, an RE71RS at about 3-4/32nd tread is likely as grippy (for 3-4 laps) as a sticker SC3R especially when heat isn't an issue in ~60deg weather.

[Bartledoo]

SC3R is substantially faster. You just weren’t using the tire’s potential. Perhaps you weren’t getting them up to temp and getting less than peak grip from them as a result. The SC3R is a bit different from the other “street” tire offerings.

Also, sounds like you were struggling with understeer, so blasting the already susceptible outside should could make sense from that, particularly if you have the tires running at preset cold (i.e. low) pressures during that. You have to build up temp before sending it on a slick or slick-like SC3R.

[rhyary]

M1500Z

Hi,
if you want to send me your two AIM sessions, one with the 71S and the other with the GY SC3Rs , I can answer your question better without guessing

Send me private message

[tsk94]

Originally Posted by rhyary

M1500Z

Hi,
I you want to send me your two AIM sessions, one with the 71S and the other with the GY SC3Rs , I can answer your question better without guessing

Send me private message

🤔

[chocstraw]

Originally Posted by M1500Z

appreciate any thoughts or input! ���� ����*♂️

They like a different PSI than you’d intuitively expect. Confirmed by 2 other SC3R users when I brought it up. One was a 720s, other was another E92.

One explanation I saw was that they were designed for a heavier car (the Camaro? Don’t remember)

one guy told me like 31 cold, and I did that, took a hot temp (don’t remember, sorry), then played w/ PSI and couldn’t beat the original cold / hot combo I tried.

Similar to when you set better times with softer suspension settings despite feeling like you aren’t (body roll is good sometimes!)

[M1500Z]

Appreciate the responses and now I'm thinking maybe this would've made more sense in the tire talk thread—too late for that.

As a generalized question, if adding grip, should you be adding camber or increasing roll rate with a bar adjustment? The difference between a 200 and 100tw tire didn't seem like enough to me so I left my setup the same as had been working for me.

Originally Posted by omgzirra_exe

do you have a pic of the sidewall marker?

my one time experience with S3 at 36F and 34PSI hot temp on a full weight E92 M3, on a technical track like BW in SoCal,

i think for COTA you might want to start at a higher cold temp... with a slightly higher hot temp due to more extended high speeds?

although im barely a sub 2 guy at BW so my experience isn't much...

My post is being weird but the sidewall pic should be showing up now. The wear line looks to be right where it should be. I ran the regular SC3 back in '21 when I was getting into this terrible addiction and I want to say they were pretty happy right around ~35psi hot with good wear. Very good tire for what it is—talkative too.

For these SC3 R, I started at 29psi cold to get to that 36ish hot.

Originally Posted by spxxx

I don't have SC3R experience but the RE71RS tires are magic. The SC3R is fast but you're right, an RE71RS at about 3-4/32nd tread is likely as grippy (for 3-4 laps) as a sticker SC3R especially when heat isn't an issue in ~60deg weather.

RE-71RS (ugh, why did they have to add an 's', making it look plural) really does seem like something else. For me, they are faster than RT660 and wear better/don't have splices exposed randomly. I wasn't pleased with them at full depth just due to their lack of ability to manage heat.

Originally Posted by Bartledoo

SC3R is substantially faster. You just weren’t using the tire’s potential. Perhaps you weren’t getting them up to temp and getting less than peak grip from them as a result. The SC3R is a bit different from the other “street” tire offerings.

Also, sounds like you were struggling with understeer, so blasting the already susceptible outside should could make sense from that, particularly if you have the tires running at preset cold (i.e. low) pressures during that. You have to build up temp before sending it on a slick or slick-like SC3R.

Listen bud, I don't know who you think you are... but I appreciate the input . You've run both the SC3 R and new RE-71RS? Do you have any deltas (laps, pressures, etc) that may help guide me in the right direction? Sustained lateral gs are kind of tough, but using a rolling average in Aim RS3, I feel pretty comfortable stating peak lateral gs (as measured) were ~1.43 on the RE-71RS and ~1.36 on the SC3 R through T13 at COTA. If those front shoulders will last, I may be able to get another weekend out of them and make some adjustments.

I definitely read a lot about these tires prior to running them so did all the things because I was worried I'd destroy them by accident.

• ran a higher cold pressure
• got them up to what I believe was operating temp before going at pace
• tried to be a little less ham-fisted

To get them up to temp, I increased pace to about 80% over the first 2 laps and tried to put heat into the carcass with acceleration and braking, then I'd go for it. They definitely are sketch cold—way more than any 200 I've driven.

Originally Posted by rhyary

M1500Z

Hi,
I you want to send me your two AIM sessions, one with the 71S and the other with the GY SC3Rs , I can answer your question better without guessing

Send me private message

Mmmm, maybe—I'd have to do that later though. If there's something you're looking for, share it here and I'll take a look.

Originally Posted by chocstraw

They like a different PSI than you’d intuitively expect. Confirmed by 2 other SC3R users when I brought it up. One was a 720s, other was another E92.

One explanation I saw was that they were designed for a heavier car (the Camaro? Don’t remember)

one guy told me like 31 cold, and I did that, took a hot temp (don’t remember, sorry), then played w/ PSI and couldn’t beat the original cold / hot combo I tried.

Similar to when you set better times with softer suspension settings despite feeling like you aren’t (body roll is good sometimes!)

I've seen similar musings, but I don't know how that translates to the other sizes so I kind of went off a guess and shot for ~36-37psi hot starting at 29psi cold. I've destroyed a set of tires before by running them lower PSI thinking it had more grip when really it just felt better rather than being better. I can upload a photo of my tire pressure gauge / pryometer screen later.

Originally Posted by tsk94

🤔

Let me in on the joke ;P

[DRLane]

Originally Posted by M1500Z

Appreciate the responses and now I'm thinking maybe this would've made more sense in the tire talk thread—too late for that.

As a generalized question, if adding grip, should you be adding camber or increasing roll rate with a bar adjustment? The difference between a 200 and 100tw tire didn't seem like enough to me so I left my setup the same as had been working for me.



Let me in on the joke ;P

I wouldn’t be shy about sharing your data with rhyary Getting someone willing to help that’s more than qualified to poke around your data with the advanced custom profiles and math channels he’s built in RS3. It’s a better use of time than asking random look at my tire questions between different session conditions across different days.

Hint, was probably 10+ different factors and variables resulting in your differing times.

[omgzirra_exe]

Originally Posted by M1500Z

Appreciate the responses and now I'm thinking maybe this would've made more sense in the tire talk thread—too late for that.

As a generalized question, if adding grip, should you be adding camber or increasing roll rate with a bar adjustment? The difference between a 200 and 100tw tire didn't seem like enough to me so I left my setup the same as had been working for me.



My post is being weird but the sidewall pic should be showing up now. The wear line looks to be right where it should be. I ran the regular SC3 back in '21 when I was getting into this terrible addiction and I want to say they were pretty happy right around ~35psi hot with good wear. Very good tire for what it is—talkative too.

For these SC3 R, I started at 29psi cold to get to that 36ish hot.

on a side note.. idk what tire pressure gauge your using but you should check it across your friends when pitted in after a session.. yours could be reading 35 but a friends could be reading 38, 36, 39.. etc etc

[rhyary]

M1500Z

I want to see your throttle application vs location in the turn.

for example, if the high grip SC3R led you to brake later, not fully rotating your car, and lazy applying the throttle on exit as a result, it will add lap time. This is one example on what I am looking for.

You wanted to know the difference between the two tires. I would want to start by looking at how you drove differently.

To make my point, if Sir L. Hamilton drove your car with SC3R vs you driving your car with 71RS, I am sure he will be quicker because he drives differently and the data would show how he drives differently.

Also, for 100w tires you have to generate more heat for them to be more stiky than 200tw tire. theoritically if you drove the same, you will have less traction with the 100tw tire.

It is a very complex topic. I have been down the tires rubbit hole for few years now.

Perhaps I can help.

[Cmassey3]

I noticed in the G8X track prep video, they specify to remove the water guards on the brake ducts before track use:

I checked on my E92 and it also has these duct rain guards with the same two screw removal. I'm going to try running without them on the track next session and see if that helps my front pad wear. At the moment, I'm wearing through the fronts (PFC 08) twice as fast as the rears. I'm running a stock car at the moment and this might help improve pad wear without going to GT4 style ducting.

[StripclubDJ]

Originally Posted by spooni

Also picked up this MulletMaro. Undecided on if it’ll be a track car or not. Getting some OEM Goodyear SC3 to replace the all seasons that the original owner put on.

The torque is insane. Much more fun on the street! For $37k hard to beat as much as car as this offers.

.

[spooni]

Originally Posted by StripclubDJ

.

.

[tsk94]

Originally Posted by M1500Z

Let me in on the joke ;P

No joke, really.
I'm genuinely curious how he can interrupt tire wear based on data, accurately.

In my experience, two tires will always require different pressures & alignments to wear evenly. What worked for you with the 71RS I'm not surprised to hear is not working as well with the Goodyears. Most of your photos won't load for me, so I can't offer much insight.

[M1500Z]

Originally Posted by omgzirra_exe

on a side note.. idk what tire pressure gauge your using but you should check it across your friends when pitted in after a session.. yours could be reading 35 but a friends could be reading 38, 36, 39.. etc etc

I use 2 gauges at the track and they read identical—one Longacre digital and the other is a Prisma Electronics digital pressure/pyrometer tool (neat tool, wonky UX).

Originally Posted by rhyary

M1500Z

I want to see your throttle application vs location in the turn.

for example, if the high grip SC3R led you to brake later, not fully rotating your car, and lazy applying the throttle on exit as a result, it will add lap time. This is one example on what I am looking for.

You wanted to know the difference between the two tires. I would want to start by looking at how you drove differently.

To make my point, if Sir L. Hamilton drove your car with SC3R vs you driving your car with 71RS, I am sure he will be quicker because he drives differently and the data would show how he drives differently.

Also, for 100w tires you have to generate more heat for them to be more stiky than 200tw tire. theoritically if you drove the same, you will have less traction with the 100tw tire.

It is a very complex topic. I have been down the tires rubbit hole for few years now.

Perhaps I can help.

Appreciate it—sent you a DM with links to files/video. Always interested to learn more about data and analysis strategies, and curious to see what you find.

Originally Posted by tsk94

No joke, really.
I'm genuinely curious how he can interrupt tire wear based on data, accurately.

In my experience, two tires will always require different pressures & alignments to wear evenly. What worked for you with the 71RS I'm not surprised to hear is not working as well with the Goodyears. Most of your photos won't load for me, so I can't offer much insight.

Tried (again) to fix those photos—google photos letting me down. Hopefully rhyary finds something interesting in there.

[DRLane]

Originally Posted by tsk94

No joke, really.
I'm genuinely curious how he can interrupt tire wear based on data, accurately.

In my experience, two tires will always require different pressures & alignments to wear evenly. What worked for you with the 71RS I'm not surprised to hear is not working as well with the Goodyears. Most of your photos won't load for me, so I can't offer much insight.

That’s fair, I was referring to the “why was I slower with a faster tire”. That should be easy to spot.

Edit: although you can find understeer in data and then look at inputs (throttle and steering angle) to see its driver induced which would signify push dragging the tire and thus accelerated wear. Or am I thinking about it wrong?

[Ximian]

Originally Posted by Cmassey3

I noticed in the G8X track prep video, they specify to remove the water guards on the brake ducts before track use:

I checked on my E92 and it also has these duct rain guards with the same two screw removal. I'm going to try running without them on the track next session and see if that helps my front pad wear. At the moment, I'm wearing through the fronts (PFC 08) twice as fast as the rears. I'm running a stock car at the moment and this might help improve pad wear without going to GT4 style ducting.

Are you sure your E92 has the rain guards? I've been in the wheel wells several times and don't recall that. There is a cover for the headlight access, but that's high up.

My G80 gets filled with garbage and dead bugs because there's air intake ducts behind those covers. Removing them does reduce temperatures on track.

[omgzirra_exe]

Originally Posted by Cmassey3

I checked on my E92 and it also has these duct rain guards with the same two screw removal.

i dont even have that on my car anymore

[Cmassey3]

Originally Posted by Ximian

Are you sure your E92 has the rain guards? I've been in the wheel wells several times and don't recall that. There is a cover for the headlight access, but that's high up.

My G80 gets filled with garbage and dead bugs because there's air intake ducts behind those covers. Removing them does reduce temperatures on track.

Based on this fender liner diagram, there's two potential spots it could be in the liner, either section 10 or section 16.

https://www.realoem.com/bmw/enUS/sho...diagId=51_5862

I haven't poked around yet to find out.